We propose to study familial visceral myopathy by doing: 1. Studying the history of the disease by long-term follow-up of identified cases. 2. Search for characteristic physical findings of the disease. 3. Study the pathology and pathophysiology of extra-gastrointestinal smooth muscle. 4. Perform repeated studies of intestinal manometry and intestinal myoelectric activity in the following patients: a. Symtomatic patients during symptomatic and asymptomatic periods. b. Asymptomatic patients. 5. Continue to evaluate and search for the best surgical treatment for symptomatic patients. 6. Seek new kindreds. 7. Study of collagen synthesis, myosin synthesis and total protein synthesis in smooth muscle cell cultures obtained from duodenal and jejunum biopsies of controls and patients with familial visceral myopathy. 8. Evaluation of influence of in vitro addition of membrane stabilizing drugs such as diphenylhydantoin and ionophore A23187 on collagen synthesis, myosin synthesis and total protein synthesis in smooth muscle cell cultures. 9. Study of creatine phosphokinase (CPK) in smooth muscle cell cultures. 10. Study of heart by clinical evaluation, electrocardiogram studies. 11. Study of striated muscle by clinical evaluation, electromyography and muscle biopsy.